Epidemiology of meningococcal disease and a community outbreak in Somerset.

We describe the epidemiology of meningococcal disease in Somerset and a community outbreak in one district. Fifty-seven cases of meningococcal disease occurred in residents of Somerset between 1 May 1990 and 30 April 1993 (incidence 4.7/100,000/year), of whom six died. Thirteen of the cases occurred in one local authority area in a six month period from 1 November 1992 to 30 April 1993; an incidence of 26.6/100,000/year. Twenty-seven patients were given benzyl-penicillin before admission to hospital. General practitioners were significantly more likely to give benzylpenicillin to patients with rashes. The proportion that received prophylaxis tended to increase after a press release was issued and general practitioners were advised. The number of cases was too small to demonstrate the protective effect of early administration of benzylpenicillin. In five cases the consultant in communicable disease control was not informed for over 12 hours. Thirty-seven of the 48 index cases for whom information was available received rifampicin prophylaxis before discharge from hospital.